Pesticidal phosphorus esters



United States Patent 2,882,198 PESTICIDAL PHOSPHORUS 'ESTERS Joe R. Willard and John F. Henahan, Middleport, N.Y.,

- assignors to Food Machinery and Chemical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Original application July 16, 1956, Serial No. 597,886. Divided and this application May 19, 1958, Serial No. 739,959

2 Claims. (Cl. 167-30) unique pesticidal activity, in that they function as eflfective active ingredients in insecticidal compositions, acaricidal compositions and ovicidal compositions. The subject compounds have the general formula wherein X is oxygen or sulfur, R is hydrogen or an organic radical, and R, R R and R are organic radicals.

Compounds of this general type have reportedly been" methylene esters of this type may be prepared from a.

methylene dihalide having the general formula YCHRZ wherein Y and Z may be chlorine or bromine. In addition to hydrogen, the R group of the dihalide may be a hydrocarbon radical such as alkyl, aryl, cycloalkyl, aralkyl, alkaryl and the like, or R may be a substituted hydrocarbon, containing groups such as chloro, bromo, nitro, alkoxy, hydroxy and the like, or R may be a functional group such as carbalkoxy, carbamido, carbanilido, halogen, alkoxy, nitro and the like. The use of the halide rather than the aldehyde greatly enlarges the number and types of substituents which may be represented by R.

The methylene dihalide is condensed with a metallic salt of a thioor dithiophosphoric acid, of the formula ammonium and silver salts, generally in the presence of a solvent. The radicals R and R may be hydrocarbon radicals such as alkyl, cycloalkyl or aryl, for example,

or they may be substituted hydrocarbons containing such substituents as chloro, bromo, alkoxy, nitro, and the like. Generally R and R correspond to R and R although they may be difierent if the reaction is carried out in two stages.

In the preferred process of this invention, two molar equivalents of the appropriate phosphorothioic or phosphorodithioic acid is dissolved in a solvent such as ethanol or dioxane, and a solution of the metal hydroxide is added until the pH is about seven. A 25-40% solution of potassium hydroxide in ethanol is a convenient reagent. A preformed salt of the phosphorus acid may also be used, dissolved in a solvent. To the neutral solu- 2,882,198 Patented Apr. 14, 1 959 EXAMPLE 1 Bis (S- diethoxyphosph-inothioyl) mercapto) m'e lhane Two molar equivalents of 0,0-diethyl hydrogen phosphorodithioate were dissolved in suflicient ethanol to give a four molar solution. 20% ethauolic potassium hydroxide was added slowly, the temperature maintained below 50 during the addition, until the pH of the solution was approximately 7.0. To the neutral solution was added 1 molar equivalent of dibromomethane and the mixture was heated under reflux for six hours. The precipitated solid was isolated on a filter and the filtrate was concentrated under vacuum. The residue after removing the solvent was diluted with ether, the solution washed with two volumes of water and the ethereal layer dried. The dried solution was concentrated under vacuum to give 0.74 molar equivalent of a colorless liquid having an n Analysis: Calcd. 01 C9H2204P2S4I P 16.13, S 33.34; P/S ratio 0.50. Found: P 16.04, S 33.72; P/S ratio 0.51.

When the dibromomethane in the above procedure was replaced by chlorobromomethane, 0.78 molar equiva-' lent of colorless liquid having an n 25D 1.5285 was obtained. Bio-assay, and chemical analysis, indicated the' two products to be identical. Analysis: Calcd. for C H O P S P 16.13, S 33.34; P/S 0.50. Found: P 16.25, S 33.63; P/S ratio 0.50.

Two molar equivalents of 0,0-diccyclohexyl hydrogen phosphorodithioate was neutralized by addition of 20% ethanolic potassium hydroxide, the temperature maintained below 50 during the addition, and to the'neutral solution was added one molar equivalent of dibromomethane. The mixture was heated under reflux for 2.5 hours and the reaction mixture treated as described in Example 1 to give 0.40 molar equivalent of a viscous orange-brown liquid having an n 25D 1.5290. Analysis:

Calcd. for C H O P S P 10.32, S 21.34; P/S ratio 0.50. Found: P 10.45, S 21.29; P/S ratio 0.51.

EXAMPLE 3 (4-nitrophenyl) -bis(S-(diethoxyphosphinothioyl) mercapto) methane of potassium 0,0,-diethyl The compounds of this invention were evaluated for pesticidal activity. It was found that all were not equivalent in activity, but that some were superior as insecticides, some as acaricides and some as ovicides, and that some showed systemic activity as well. Some of the compounds in this group showed an unusually broad range of activity characterized by high toxicity.

The pesticidal compositions may be formulated as aqueous emulsions, as dry or wettable powders, as solu- EXAMPLE 4 I l trons, or in any other suitable vehicle. The composiyl p y p methane tions can be utilized as sprays, as dusts, as aerosol mixn (n; tures, insecticidal coating compositions, and as residues.

In general, they can be applied by methods commonl 021150 f S CHFS P 002115 used for control or eradication of insects, mites and thie 0955 C135 like. Thus, these compositions may be formulated with To an ethanolic solution containing 2 molar equivalents of sodium 0,0-diethylphosphorothiolate, prepared by reaction of elemental sulfur with 0,0-diethyl phosphite according to the procedure of Fiszer et al. (Chem. Abstracts, 49, 3786(1955)), was added one molar equivalent of dibromomethane. The reaction mixture was heated under reflux for six hours and the product recovered as described in Example 1, to give 0.23 molar equivalent of dark red liquid having an n D 1.4678. Analysis: Calcd. for C I-I O P S P 17.58, S 18.20; P/S ratio 1.00. Found: P 19.80,. S 20.40; P/S ratio 1.00.

In Tables 1 and 2, which follow, are tabulated the descriptions, refractive indices and analyses of a number of compounds of this invention which have not before been described or characterized in the chemical literature. These compounds may be prepared by procedures similar to those described in the foregoing examples.

solvents, diluents, and carrier media, adhesives, spreading, wetting and emulsifying agents and other ingredients. A typical formulation used in evaluating the toxicants of this invention is a wettable powder containing 25% TABLE 1.-PHOSPHINOTHIOYL- AND PHOSPHINYLMEROAPTO- ME'IHANES Compound Analysis B R X Theory Found Methy Methyl S 1. 6247 P-lS. 89 19-17. 39 Ethyl--- Ethyl S 1. 5315 P-16. 13 P-16.04 Dod0 O 1. 4678 P-17. 58 P-l9. n-Propyln-Propyl.-. S 1. 5220 P-14. 08 1 -14. 04 IsopropyL- Isopropyl-.. S 1. 5163 P-14. ()8 P-14. 06 n-Bu n-Buty S 1.5110 19-1249 P-12. 18 Isohntyl Isobuiry 5 1.5088 P12.49 1 -12. 18 Ethyllisopropyl (1:1) Ethyllisopropyl (1:1) S 1. 5258 P-15. 04 P4509 Ethyl/isopropyl (3'1) Ethy1/isopropyl(3:1) 8 1.5298 P-15. 57 $945.60 GyclohexyL- Cyclohexyl S 1. 5290 P10.32 P-10.49 P 511? 2 t 2532 1 3-5 1 2?? -Ch1oro hen 1-. porop eny p yl Phenyl S 1. 5350 P12.87 1 -12. 47

TABLE 2.SUBSTITUTED IZJHOSPHINOTHIOISFL- AND PHOSPHINYLMER- APTOMETHANE I. i it RO-P-SCHS-POR' Compound Analysts R R R X Theory Found S 1. 5497 P-li. 47 P-12. 91 O 1. 5170 S 1. 5853 P-9. 66 P-10. 20 d0 S 1. 5630 P-7. 94 P-8. 08 2,6-dichlorophenyL- S I. 5712 P-ll. 70 P-11. 95 4-nitrophenyl- S l. 5753 P-12. 25 P-12. 20 -r. do O 1. 5352 8-13. 55 8-12. 95 Oarbethoxy S 1. 5123 N,N-ditheyl-carbamido- S 1. 5078 ZIP-12. 87 .P-12. 51 N-phenylearbam1d0 S 1. 5532 Table 3 below represents the results of screening tests of various bis(S- (dialkoxyphosphinothioyl)mercapto) methanes. A number of these compounds exhibited residual, slow acting or ovicidal activity against twospotted mites, and residual activity against Mexican bean beetles and pea aphids. A plus sign in Table 3 indicates significant ovicidal activity.

Pursuant to the requirements of the patent statutes, the principle of this invention has been explained and exemplified in a manner so that it can be readily practiced by those skilled in the art, such exemplification including what is considered to represent the best embodiment of the invention. However, it should be clearly understood that, within the scope of the appended claims, the inven- TABLE 3.INITIAL CONTACT ACTIVITY olgE li ggogslALKoxYPHosPfllNoTHIOYL)MERCAPTO) R II I II R'OPSCHSPOR' Compound Percent kill at 1,250 p.p.m.

Two-spotted mites Ger- Mexl- South- R' R R X man can ern Pea roach bean armyaphid Adults Nymphs Ova beetle worm Methyl Methyl Hydrogen S 96 75 0 0 0 0 thyl Ethyl do S 100 100 100 100 95 100 Do do (in O 100 100 100 100 6 100 Isopropyl. Isopropyl do S 95 90 0 50 100 65 Phenyl heny S 100 100 0 90 0 0 4-ch1orophenyl... 4-ehlorophenyl --do S 100 100 0 100 0 0 Ethyl Phenyl do S 100 100 90 100 0 D0 Ethyl Carbethoxy S 100 100 100 100 100 45 Do (in Phenyl S 100 100 0 100 15 0 Do do 2,6-diehlorophenyl S 91 95 0 0 60 0 Do do NgI-diethylcarbami- S 100 100 100 100 100 0. Do do N-pheny1earbamiclo S 100 100 55 10 To measure ovicidal activity, horticultural bean plants were infested with adult two-spotted mites. A period of four to five hours was allowed for the deposition of eggs. The ovicidal materials were then applied to the eggs by dipping the leaves into aqueous suspensions of wettable powder formulations of these materials one and three days after infestation. Ovicidal activity against Mexican bean beetle ova was measured by dipping one-day-old egg masses in an aqueous suspension of a wettable powder formulation of the test material and maintaining the wet egg masses at room temperature for 6 days.

Test results are shown in Table 4, for ovicidal activity of bis (S (diethoxyphosphinothioyl)mercapto)methane against Mexican bean beetle and two-spotted mite eggs.

TABLE 4.OVICIDAL ACTIVITY OF BIS-(S-(DIETHOXY- PHOSPHINOTHIOYL)MERCAPTO)METHANE.

Cone. of

and an inert pesticidal adjuvant as carrier therefor.

2. A method for controlling mite and insect pests and ova which comprises contacting said pests and ova with an effective concentration of the compound bis(S-[diethoxyphosphinothioyllmercapto) (pheny1)methane.

References Cited in the file of this patent UNITED STATES PATENTS 2,266,514 Romieux Dec, 16, 1941 2,596,076 Hook May 6, 1952 2,736,737 Morris Feb. 28, 1956 

1. A PESTICIDAL COMPOSITION COMPRISING AS AN ACTIVE INGREDIENT A TOXIC CONCENTRATION OF THE COMPOUND BIS(S(DIETHOXYPHOSPHINOTHIOYL) MERCAPTO)(PHENYL) METHANE OF THE FORMULA 